Synthesis and Polymerization of a Four-Arm Star with Pendent Cyclopentadienyliron Moieties

The synthesis of the title complex was achieved via the reaction of a η⁶-p-dichlorobenzene-η⁵-cyclopentadienyliron cation with an organic four-arm core to produce the tetrairon complex. This tetrairon-containing core was subsequently polymerized via nucleophilic aromatic substitution with various dinucelophiles such as 4,4′-thiobenzenethiol, bisphenol-A, 4,4′-(1-phenylethylidene)bisphenol, 4,4′-biphenol, bis(4-hydroxyphenyl)methane, producing five different cross-linked cationic organoiron polymers. Another cross-linked polymer was produced via direct polymerization of the four-arm organic core with the η⁶-p-dichlorobenzene-η⁵-cyclopentadienyliron cation. Due to the poor solubility of these cross-linked polymers, solid-state ¹³C CPMAS NMR was performed in order to verify that polymerization was successful. Thermogravimetric analysis (TGA) revealed that following the decoordination of the cyclopentadienyliron moieties, the polymers were thermally stable. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (T _g’s) ranging from 104 to 146°C. This article is dedicated to Professor Ian Manners for his outstanding contribution to the field of metal-containing polymers.     

Polymerization of Methacrylates Containing Cationic Cyclopentadienyliron Moieties

A novel approach to the synthesis of polymethacrylates containing cationic cyclopentadienyliron moieties pendent to their side chains was accomplished via the use of -coordinated organoiron complexes. The complexed methacrylates were polymerized in the presence of AIBN to give soluble organoiron polymethacrylates (6a and 6b, 10, 14a and 14b) in 80–90% yields. Photolytic demetallation of the organoiron polymers allowed for the isolation of their organic analogues (7a and 7b, 11, 15a and 15b) whose weight average molecular weights ranged from 48,500 to 68,300.     

Synthesis and Polymerization of Cationic bis(cyclopentadienyliron)arene Complexes Containing Arylazo Dyes

The synthesis of the title complexes was achieved via the reaction of -p-dichlorobenzene- -cyclopentadienyliron cations with 4,4′-bis(4-hydroxyphenyl)valeric acid to produce the diiron complexes which were then reacted with a number of arylazo dyes to give cationic bis(cyclopentadienyliron)arene complexes containing the arylazo dyes. These iron-containing monomers were subsequently polymerized via nucleophilic aromatic substitution using 1,8-octanedithiol, 4,4′-thiobisbenzenethiol, or bisphenol A to produce the desired coloured cationic organoiron polymers. The weight – average molecular weights were estimated to range from 11,800 to 31,600. UV–vis studies conducted in dimethylformamide (DMF) showed that the metallated polymers exhibited of 412–491 nm. Addition of HCl to the polymer solution caused a bathochromic shift into the range of 515–530 nm. Thermogravimetric analysis (TGA) revealed that the iron moieties were cleaved between 205 and 248 °C while the polyether/thioether backbone degraded between 380 and 613 °C. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (Tg) ranging from 106 to 184°C.This paper is dedicated to Professor Richard J. Puddephatt in recognition of his outstanding contribution to the field of metal-containing polymers.     

Synthesis and Characterization of Novel Organoiron Polymers

Synthesis of novel organoiron polymers containing oxygen, sulfur, and/or nitrogen bridges was achieved via nucleophilic aromatic substitution polymerization of cyclopentadienyliron complexes of chloroarenes with a number of aliphatic and aromatic dinucleophiles.     

First Example of Benzothiazole Azo Dyes Containing Cyclopentadienyliron Polynorbornene Macromolecules

Soluble cationic organoiron polynorbornenes with pendent hetarylazo side chains have been synthesized via ring opening metathesis polymerization (ROMP) using bis(tricyclohexylphosphine)benzylideneruthenium(IV) dichloride (Grubbs' catalyst). The vibrantly colored organoiron polymers displayed weight average molecular weights between 24500 and 40900 and exhibited glass transition temperatures at 146 °C and 161 °C.     

Synthesis and characterization of polyesters containing fluorescein dye units

Low molecular weight polyesters containing fluorescein units in their backbones were successfully synthesized. These fluorescent polymers showed a high solubility in most of the common organic solvents. The onset degradation temperatures of the polymers were greater than that of fluorescein. The glass transition temperatures were in the range 126-194 °C. The bathochromic fluorescence emissions in organic solutions at high concentrations, which resulted from the aggregation of fluorescein moieties, were prohibited by protecting the OH end groups with benzoyl groups. The polymer powders exhibited a maximum photoluminescence intensity at about 580 nm.     

Synthesis of some fumaric acid polyamides from active diester monomers

Summary The solution polycondensation of two active diesters, bis(2,4-dinitrophenyl) fumarate and 1,1-(fumaroyldioxy)bis(benzotriazole), with a series of alphatic and aromatic diamines in N-methyl pyrolidone at room temperature, was investigated. The polycondensation reactions yielded a series of fumaric acids polyamides. The polymers obtained from aliphatic diamines were soluble in trifluroacetic acid and exhibited well-defined melting points. The polymers obtained from aromatic diamines are infusible at temperatures below 300°C but were thermally stable and soluble in dimethylacetamide containing 4% LiC1.     

Synthesis,characterization, and thermal behaviour of new epoxy polyesterimides

New epoxy resins have been synthesized by the reaction of diimide-diacids trimellitimide derivatives containing different aliphatic and aromatic fragments in N-methyl pyrrolidone (NMP) with their corresponding diglycidylesters, using several molar ratios. The polymer composition has been determinated by chemical and elemental analyses. Their IR, ¹H, and ¹³C NMR spectral data allowed to confirm the structural unit. Epoxy polyesterimides are soluble in polar organic solvents and show good thermal resistance. Differences on the basis of the introduced aliphatic or aromatic fragments were observed.     

Hyperbranched Polymers Containing Cyclopentadienyliron Complexes

A number of hyperbranched polymers containing cyclopentadienyliron moieties were prepared using the A₂+B₃ method. The A₂ compounds used were common diols, dithiols or dichloroarenecomplexes. B₃ compounds included either prepared star-shaped molecules or a purchased triol. The effect of the reaction conditions on the properties of the products was probed. Analysis of the prepared polymers was conducted using ¹H and ¹³C NMR, viscometry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Viscometry values were generally found to be low, in the range of 0.175–0.300 dl/g. TGA showed losses starting at approximately 230°C and ending at 280°C, corresponding to the decomposition of the cyclopentadienyliron moiety. Degradation of the polyether backbone was found to occur starting at 390–567°C. Glass transition temperatures were found to be between 60 and 134°C, whereas melting temperatures ranged from 155 to 190°C.     

Synthesis and Thermal Properties of Polycarbonates Based on Bisphenol A by Single-phase Organic Solvent Polymerization

Linear alternating polycarbonates optionally containing bisphenol A were prepared from the reaction of linear aliphatic, substituted aliphatic, cyclic aliphatic and aromatic dihydroxy compounds with bisphenol A bischloroformate at 0–5 °C using a single organic phase as a reaction medium (e.g., Chloroform or tetrahydrofuran). Twelve aromatic–aromatic and aromatic–aliphatic polycarbonate polymers were prepared utilizing this procedure. The effect of the experimental conditions on the polymerization was studied and discussed. The polymers obtained were characterized by IR spectra, ¹H and ¹³C NMR spectra, inherent viscosity, differential scanning calorimetry, and thermogravimetric analyses.     

Study of the incorporation of protic ionic liquids into hydrophilic and hydrophobic rigid-rod elastomeric polymers

A series of polymers was synthesized that contain a rigid aromatic backbone connected through triazine linkages that are cross-linked by flexible diamine-terminated poly(ethylene oxide) oligomers. Polymers were made that contained both hydrophilic sulfonated aromatic and hydrophobic pyridinium triflate backbones. Thermal and mechanical properties of the resulting polymer films were studied, as well as uptake of water and protic ionic liquids. Ionic liquid uptake varied from 41 to 440%, depending upon the nature of the polymer. The ionic liquid-doped films were analyzed for proton conductivity at high temperatures (>150 °C) under non-humidified conditions. Conductivities as high as 5×10⁻² S/cm were observed at 150 °C.     

New hyperbranched polymers containing second-order nonlinear optical chromophores: Synthesis and nonlinear optical characterization

Three hyperbranched polymers (P1-P3) containing second-order nonlinear optical chromophores were synthesized by copolymerization of aromatic dialdehydes (carbazole, triphenylamine or benzene moieties) with sulfonyl-based chromophores attached with three active methylene groups, from “A₂ + B₃” approach based on simple Knoevenagel reaction. For comparison, their corresponding linear analogue polymers (P4-P6) were prepared. All the polymers are soluble in common organic solvents, and exhibit good thermal stability. The tested NLO properties of the hyperbranched polymers are better than their corresponding linear polymers, due to the three-dimensional spatial separation of the chromophores in the obtained hyperbranched polymeric structures.     

Direct synthesis of soluble and thermally stable poly(urethane-imide)s from a new triimide-dicarbonylazide

A new aromatic dicarbonylazide (3) bearing three preformed imide rings was synthesized by treating N-[3,5-bis(trimellitimido)phenyl]phthalimide (1) with thionyl chloride followed by a nucleophilic reaction with sodium azide. A novel family of fully aromatic poly(urethane-imide)s with inherent viscosities of 0.19-0.24 dl g⁻¹ were prepared from triimide-dicarbonylazide 3 and various aromatic diols. The polyaddition reactions readily proceeded in desirable yields as one-pot reactions starting from 3 without separately synthesis of the corresponding diisocyanate. All of the resulted polymers were thoroughly characterized by spectroscopic methods and elemental analyses. The poly(urethane-imide)s exhibited an excellent solubility in a variety of polar solvents. Crystallinity nature of the polymers was estimated by means of WXRD. The glass transition temperatures of the polymers determined by DSC method were in the range of 197-219 °C. The 10% weight loss temperatures of the poly(urethane-imide)s from their TGA/DTG curves were found to be in the range of 391-412 °C in nitrogen. The films of the polymers were also prepared by casting the solution.     

Soluble rigid rod-like polyimides and polyamides containing curable pendent groups

Soluble rod-like aromatic polyimides and polyamides containing curable pendent groups were synthesized. The polyimides (PIEANs) and polyamides (PAEANs) containing pendent enaminonitrile groups showed good thermal stability, and underwent curing reactions without the emission of volatile by-products above 300 °C to stable materials which were not soluble in any organic solvents. However, the polyimides (PIEONs) and polyamides (PAEONs) containing pendent enoxynitrile groups started to decompose around 300 °C, because of the instability of enoxynitrile groups. PAEONs underwent curing reactions around 420 °C in spite of the initial decomposition, but PIEONs exhibited only thermal degradation process. Thermal analyses of these polymers and the corresponding model compounds revealed that the curing of enaminonitrile groups proceeded via intermolecular crosslinking as well as intramolecular cyclization, while the enoxynitrile groups, known to undergo self-curing reaction, could not be cured by itself, and a reactive amine group was essential for the curing of the enoxynitrile groups.     

Crisscross addition polymerization of alkyl aldazines and 1,4-phenylene diisocyanate

Crisscross addition polymerization of alkyl aldazines (i.e., acetaldehyde azine, propionaldehyde azine, and butyraldehyde azine (BuAz)) and 1,4-phenylene diisocyanate (Ph(IC)₂) was investigated under various conditions. The crisscross addition polymerizations in pyridine yielded polymers in higher yields. The polymers obtained in the present study exhibited very limited solubilities and contained fractions insoluble in conventional organic solvents. However, since the BuAz/Ph(IC)₂ polymers obtained at 24 and 48 h were soluble in pyridine, the M_w values for these polymers were determined to be 2.2 × 10³ and 4.4 × 10³, respectively, by small angle X-ray scattering. These data indicated that molecular weights of the pyridine-insoluble polymers were as high as or close to 10⁴. IR, ¹H NMR, and MALDI-TOF-MS data confirmed the formation of linear polymers by crisscross addition polymerization. Thermogravimetric analyses indicated that the polymers were considerably decomposed in the region of 300-400 °C, but the polymers exhibited residual weights of 15-25% even at 500 °C. Differential scanning calorimetry data indicated that glass transition temperatures for the polymers were higher than the onset of decomposition presumably because of the rigid backbone.     

Poly(pyridinium salt)s with organic counterions derived from an aromatic diamine containing oxyethylene unit exhibiting amphotropic liquid-crystalline and photoluminescence properties

Several poly(pyridinium salt)s containing various organic counterions and oxyethylene unit in their backbones were synthesized by either the ring-transmutation polymerization reaction of 4,4′-(1,4-phenylene)bis(2,6-diphenylpyrylium tosylate) with 1,2-bis(4-aminophenoxy)ethane on heating in dimethyl sulfoxide or the metathesis reaction of the tosylate polymer with the corresponding lithium or sodium salts in acetonitrile. Their chemical structures were determined by ¹H and ¹³C NMR spectroscopy, and elemental analyses. Their number-average molecular weights and polydispersity indices were in the range of 59,000-63,000 and 1.41-1.65, respectively, as determined by gel permeation chromatography. They were characterized for their thermotropic and lyotropic liquid-crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. Since these polymers exhibited liquid-crystalline phase both in the melt and in solutions, they belong to an amphotropic class of ionic polymers. Their light-emitting properties both in polar organic solvents and in films cast from methanol and acetonitrile were also studied by using spectrofluorometry.     

Synthesis and Properties of Noncoplanar Rigid-rod Aromatic Polyamides Containing Phenyl or Naphthyl Substituents

A series of novel aromatic polyamides having noncoplanar biphenylene units in the main chain and bulky naphthyl or phenyl pendant group at 2,2′-disubstituted position were prepared from the two rigid-rod aromatic dicarboxylic acid monomers, 2,2′-diphenylbiphenyl-4,4′-dicarboxylic acid (1) and 2,2′-dinaphthylbiphenyl-4,4′-dicarboxylic acid (2), and various aromatic diamines. These polyamides were readily soluble in many organic solvents and showed excellent thermal stability associated with high glass-transition temperatures in the range of 229–292°C. These polymers also exhibited strong UV–Vis absorption bands at 262–353 nm in NMP solution, and their photoluminescence spectra showed maximum bands at 440–462 nm in the purple to blue region. The poly(amine–amide) IId derived from the diamine with triphenylamine moieties revealed excellent electrochromic contrast and coloration efficiency, changing color from the pale yellowish neutral form to green then to the blue oxidized forms when scanning potentials positively from 0.00 to 1.30 V. Figure Graphical Abstract. A series of novel aromatic polyamides having noncoplanar biphenylene units in the main chain and bulky naphthyl or phenyl pendant group at 2,2′-disubstituted position were prepared from the two dicarboxylic acids and various aromatic diamines. These polyamides were readily soluble in many organic solvents and showed excellent thermal stability associated with high glass-transition temperatures in the range of 229–292°C. These polymers also exhibited strong UV–Vis absorption bands at 262–353 nm in NMP solution, and their photoluminescence spectra showed maximum bands at 440–462 nm in the purple to blue region. The poly(amine–amide) IId derived from the diamine with triphenylamine moieties revealed excellent electrochromic contrast and coloration efficiency, changing color from the pale yellowish neutral form to green then to the blue oxidized forms when scanning potentials positively from 0.00 to 1.30 V.     

Liquid crystalline polyesters by staged-addition polycondensation

Summary A series of model liquid crystalline (LC) polyesters have been prepared by low temperature solution polycondensation using staged addition methods. The model thermotropic polyesters were composed of aliphatic spacers and mesogenic groups made from substituted terephthalic acid and methyl hydroquinone. Both the mesogenic groups and the spacers were placed in the main chain. Attractive properties of these polymers include solubility in many organic solvents such as THF and DMSO with softening temperatures below 150°C. Some of these polymers show no melting transitions, and depending on the terephthalate group substituent, either smectic or nematic phases are formed. Results from GPC analysis show good solubility of polymers in THF with M_w lower than 10,000 compared to polystyrene standards. The synthesis and characterization of these LC polyesters are reported here.     

New fluorinated poly(1,3,4-oxadiazole-ether-imide)s

New fluorinated poly(1,3,4-oxadiazole-ether-imide)s have been prepared by solution polycondensation reaction of different aromatic diamines having preformed 1,3,4-oxadiazole ring, such as 2,5-bis(p-aminophenyl)-1,3,4-oxadiazole, 2,5-bis[p-(4-aminophenoxy)phenyl]-1,3,4-oxadiazole, 2,5-bis[p-(3-aminophenoxy)phenyl]-1,3,4-oxadiazole, 2-(4-dimethylaminophenyl)-5-(3,5-diaminophenyl)-1,3,4-oxadiazole and 2-(4-fluorophenyl)-5-(3,5-diaminophenyl)-1,3,4-oxadiazole, with an aromatic dianhydride incorporating ether linkages and hexafluoroisopropylidene group, namely 1,1,1,3,3,3-hexafluoro-2,2-bis-[(3,4-dicarboxyphenoxy)phenyl]-propane dianhydride. The polymers were easily soluble in polar organic solvents, such as N-methylpyrrolidinone, N,N-dimethylformamide, and pyridine, as well as in certain low boiling-point organic solvents, such as tetrahydrofuran and chloroform. Very thin coatings deposited onto silicon wafers exhibited smooth, pinhole-free surface in atomic force microscopy. The polymers showed high thermal stability with decomposition temperature being above 410 °C. They exhibited a glass transition in the temperature range of 183-217 °C, with reasonable interval between glass transition and decomposition temperature. Solutions of some polymers in N,N-dimethylformamide exhibited blue fluorescence, having maximum emission wavelength in the range of 411-424 nm.     

Synthesis and properties of amphotropic hydrogen bonded liquid crystalline (LC) poly(ester amide)s (PEA): effect of aromatic moieties on LC behavior

Twelve hydrogen bonded aromatic-aliphatic poly(ester amide)s differing in the structures of their aromatic moieties (isophthalic, terephthalic, 2,6-naphthyl and 4,4′-biphenyl moieties of the dicarboxylic acid and phenylene and xylylene moieties of the amido diol part) were prepared by the polycondensation of amido diols with acid chlorides of isophthalic acid, terephthalic acid, 2,6-naphthalic dicarboxylic acid and 4,4′-biphenyl dicarboxylic acid, respectively. The amido diols were prepared by the aminolysis of γ-butyrolactone with hexamethylene diamine, para phenylene diamine and para xylylenene diamine, respectively. The PEAs were characterised for elemental analysis, FTIR, ¹³C NMR, TGA, DSC, POM, isothermal viscosity measurements and WAXD. Here we are presenting the effect of aromatic moieties on the thermotropic and lyotropic (amphotropic) properties of PEAs. These PEAs are essentially constituted of six types of structural entities, i.e. isophthalic, terephthalic, 2,6-naphthalic and 4,4′-biphenyl moieties containing dicarboxylic acid and the aliphatic, aromatic (phenylene and xylylene moieties) of the di-amide linkage of the amido diol part. The structure of the polymers even in the mesophase is dominated by hydrogen bond interaction between the adjacent chains and also inter plane mesogenic interaction between the rigid aromatic group. It was observed morphologically that the formation of different forms of nematic/smectic/columnar/spherullitic phases in PEAs are due to the delicate balance of self assembling through hetero intermolecular hydrogen bonded amide-amide and amide-ester net works and also inter-plane mesogenic interactions.